Machine tool



F. H. BOGART MACHINE TOOL 4 Sheets-Sheet 1 Filed Jan. 11, 1945 I".bll'lal'lllllifirll-mvtll INVENTOR. Fee-'0 H. Bose/e7- firrae/vzys y1948- F. IH.'BOGART MACHINE TOOL Filed Jan. 11, 1945 4 Sheets-Sheet 2 WH w m F. H. BOGART May- 4, 1948.

MACHINE TOOL Filed Jan. 11, 1945 4 Sheets-Sheet 3 HIIIIIHIIII INVENTOR.FeED H. 506/98 7' 44M m w wmm F. H. BOGART MACHINE TOOL May 4, 1948.

4 Sheets-Sheet 4 Filed Jan.. 11, 1945 INVENTOR. FEED H- B asae 7' i atented May 4, i943 UNITED star TENT OFFIC MACHINE TOOL Application January11, 1945, Serial Nor-5723i;

Claims.

This'ihve'ntion relates to a machine tool and more particularly to thecollet chuck operating mechanism of other working machine tool.

' In the operation of bar Working machine tools the operator adjusts thechuck actuating mechanism in accordance with the diameter of the bar ofstock to be gripped by the chuck. In the event that the operator, afterhaving adjusted th chuck actuating mechanism for a certain diameter ofstock, shouldinsert a bar of stock of larger diameter in the chuck thevarious parts of the chuck actuating mechanism will not move to fullyclosed or stock gripping position, and if forced-in an eiiort to bringsuch parts fully into such position, there is the likelihood of damageorv breakage to certain of the parts. In the case of a manually operatedchuck actuating mecha nismthe operator can tell by the feel or theresistance to the movement of the operating handle whether or not thevarious parts of the actuating mechanism are in'full chuck closed orstock gripping position. Also it would be most exceptional if theoperator possessed sufficient strength. tov 'force the parts to anextent which would damage. or break the same. However, Where'the chuckactuating mechanism includes a power arrangement for closing the chuckas, for example; an arrangement such as is shown in my copendingapplication-Serial No 548,829, filed August 10, 1944, there is thedanger that the various parts of the chuck actuating mechanism might bedamaged or broken since the power force applied to the actuatingmechanism would bedsufficient to effect this bad result and furthermorethe operator would be unable to tell by the feel of the operating handleor from observation that the various parts of the actuating mechanismare not in fully closed or work gripping position.

An object of the invention is to provide in a machine tool a colletchuck actuating mechanism which eliminates the above mentioned danger ofdamaging, bending or breaking the parts of the-mechanism shouldexcessive force be applied thereto to bring the same into fully closedor work gripping position when an oversized bar of stock has beeninserted in: the collet chuck.

Another object is to provide in a machine tool a chuck actuatingmechanism such as specified in the last named object, and. whereinprovision is made for visually indicating to the operator that thevarious parts of the actuating mechanism are not in complete or workgripping position.

Further-and-additional objects and advantages not expressly =-referredto will become apparent hereinafter during the detailed description ofseveral embodiments of theiiniintioiuwhichdsato follow.

Referring to the accompanying drawings;

Fig. 1 is asomewhat diagrammatic longitudinal sectional view through.at: 51902121611. bf thefiitk' spindle and colletchuck-oraimachinetool;withthe actuating mechanism for said chucldshovin'partly in elevation ahdpastlyain section" the parts of the actuating.mechanism heing shown in the relative positions they occupy whemthecollet chuck is fully opened. I

Fig. 2 is a view similarto Fig. Land howsthe relative positions of theparts.v ofiithe-icliucktaotwating meohanismlwhen :the. chuck :iswiuliy;grip.- ping a length of stockofthe'diameter:ionwhioh the actuatingmechanismhas'beenadiilsted.

Fig. 3 is a viewsimilar tomes; hand e/and shows in 'full lines therelativepositions assumed by the parts ofathe chuck. actuatingmeqhanismwhen an attempt has been :made to-rmov lasii parts into fully closedcor,worhgripping;position upon a length. of stockvof.too-large a'diametericertain of the partsbeingshown bpdotand dash lines in the positionto}whichtheyre-ant mati cally returned by springwmean 'under no ditionsand after the. actuating force.. has .termie nated.

Fig. 4 is a fragmentarysectipnal yawtnreuge a portion of the bedofrthe.machinetoo k line 4-4 of Fig. .L andshowsthe opcratm handl or member atthe irontofztlie bed Figs. 5, 6 and rar similar t v gs. 1,.te3;iii-,elusive, respectively, but-showing" a. cm W t different form of chucktactile g mechanism -oi a different type of collet.ohuck.-.

Fig.- 8 is shown displaced. fromthanormalre'la ionshipgjit should have;g k Figs; 9 and 10 areviewssimilarto Figs. same but showing still.anotherfoifm ofchiick actuating mechanism.

Fig. 11 is a View similar to Fig; 11) butsiic this portion of themechanisfii in ;.e1 v.ation Fig, 12 is a view similar to Fe. 9 but-she athe modified 1 actuating mechanism thereilapsed condition.

Referring to Fig. 1,,10'1 repre ent tfi w k spindle o'f abarworkingmachine "s; at e. It will be understoodthatthe work spii'idl s.tatably mounted i-n theiheadstofc'k of chine tool; and is .driven- :atdifieren through a suitable .ch'ang speed 15 not shown-as it is wellilnder stoodir i thegrt l 3 end of the work spindle which is adjacent tothe cutting tools, i. e., the right hand end as viewed in the drawing,is provided with an enlarged nose portion H which has an externallythreaded flange onto which a hood I2 is se ured- Th hood I2 is providedinternally with a conical cammingsurface l3 concentric withthe centralopening of thehood and with the bore of the spindle and which serves apurpose shortly to be described. A collet I4 is arranged within the noseH and is provided with a plurality ofvspring gripping jaws 5 with saidjaws having external conical camming surfaces l6 that cooperate with thecamming surface i3 of the hood l2, The collet M is slidable axially ofthe spindle and when forced toward the right, as viewed in the drawing,the conical surface 13 of the hood acting on the conical surfaces l6 ofthe spring jaws cam said jaws inwardlyinto work gripping engagement withthe length of bar stock 11 which proj'ects'throughthe spindle andcollet. As soon as the pressure against the collet is released, theinherent-springaction of the jaws acting through thecooperating camsurfaces causes the collet bodily to shift toward the left with theresult that the grip of the jaws on the bar of stock is released. l -i IIn order to shift the collet into work gripping position an actuatingsleeve i8 is slidably mounted in the bore of the spindle. The right handend of the sleeve 18, as viewed in the drawing, abuts the collet [4,while the opposite end of the sleeve lB'is provided with an annularshoulder 19 located beyond the end of the spindle and extending into afinger housing 20 which is adjustably screwed onto theadjacent end ofthe spindle, wherefore the housing can beadjusted axially of th'e'spindle and locked in adjusted position by means not shown as it iswellknown in the art. The housing 24 'rockably mounts levers 2| which,intheir entirety, will hereafter be designated as fingers. These leversinclude heel portions-22 engaging the shoulder IQ of the actuatingsleeve and finger portions 23 projecting exteriorly of the housing 20and carrying at their free ends rollers 24. A cone 25 is slidable on thespindle iii and said cone on its periphery is provided with a conicalcammin'g portion and a cylindrical land portion. The cone is providedwith an annular groove 26whichreceives the shoes 27 carried by theforked upper end ofan actuated lever or part 28' that is pivotallysupported at 29 onthe bed of the machine tool.

It will be seen that whenthe cone 25 is moved axially of the spindletoward the left, as viewed in the drawing, the conical camming peripheryof the cone will be brought into engagement with the rollers :24 andwill spread the fingers, causing the heel portions 22 thereof to pressagainst the shoulder IQ of the actuating sleeve [8 and thus force thesleeve and'collet toward the right to cam the collet jaws l5 intogripping engagement with the stock. The construction thus far describedis well known in the art and for the present its mode of'operation neednot be further exp ained The actuated lever 28 below its fulcrum 29 isprovidedrwith a longitudinal slot 30, which communicates at its lowerend with a longitudinal bore formed injthe end of the lever 28 and laterto be referred to. A U -shaped link 3i is pivotally connected to thelever'28 in the slot 39 and the free end of said link straddles and ispivotally connectedto'one'end'of'a part 32 of a two part link whichextends through'an opening in the bed B, the other part of which isindicated at 33. The lever 28 is provided at the slot 30 with notches 3la, into which the ends of the pin which pivotally connect the U-shapedlink 3| with the part 32 engage as shown in Fig. 3, and such engagementlimits the counterclockwise movement of the link 3!. The part 32 has athreaded end which can be screwed into a threaded bore formed in thelongitudinally split end of the part 33, wherefore the two parts can beadjustably interconnected and locked in adjusted position by lockingscrews 33a.

The longitudinal bore in the lower end of the lever 28 slidably mounts ahollow plunger 34 which is provided at its upper end with a roller 35. Acoil spring 36 is located in the bore and extends into the plunger 34,and abuts at its lower end a plug 31 screwed into a threaded lower endof said bore. The spring 36 holds the roller 35 in engagement with thelower side of the part 32 of the two-part link, and the upper side ofthe part 32 in contact with the cross portion of the U-shaped link 3| asshown in Fig. l. The spring 36 should be of sufiicient strength to movethe two-part link and the operating handle later to be referred to fromthe full line position back to ,the dash-dot line position of Fig. 3when it is attempted to close the chuck on a bar of stock of greaterdiameter than the chuck is adjusted to accommodate, all as will be morefully explained hereinafter.

The right hand end of the part 33 of the adjustable two-part link isangularly bent upwardly and is pivotally connected to the freeforked endof an operating arm or part 38 that is fixedly connected to a shaft 39rockably mounted in suitable supports in the bed B of the machine andextending to the front side thereof, as will be well understood in theart and as is clearly shown in Fig. 4. The arm 38 is provided with aportion 40 arranged to abut a lug M on the upper side of the part 33 ofthe two-part link when the parts of the chuck actuating mechanism havebeen moved to work gripping position as illustrated in Figs. 2 and 3.

As already stated, the shaft 39 extends beyond the front of the bed andthe extended end of said shaft has fixed thereto an operating handle ormember 42 by means of which the operator can rock the shaft 39 and wherea power means is provided for operating the chuck actuating mechanism,such as is shown in my copending application Serial No. 548,829, therocking of the shaft 39 will function automatically to initiate thepower drive. In my said copending application the operating shaft suchas the shaft 39, is rocked not only by means of the operating handle 42,but also is rocked by power means controlled by said handle. This powermeans may be suitably positioned relative to the shaft 39 andoperatively connected thereto, but such arrangement has not beenillustrated herein as it is fully disclosed in my said copendingapplication. In such an arrangement the first portion of the manualmovement imparted to the operating handle starts the idle movement ofthe chuck actuating mechanism while the power means subsequently comesintoaction and continues until the chuck is closed. Consequently, unlessthe mechanism embodies the instant invention, the operator cannot tellby the feel of the resistance to the movement of the operating leverwhether or not the parts of the chuck actuating mechanism have beenmoved to full work gripping position. Also in such an arrangement wherea bar of stock of too great a diameter has been placed in the chuck thepower means will continue to exert force againstuthe parts oftheactuatingmechanism, eventhough the jaws and the parts I cannot :moveto full'work gripping position with the likelihood of damaging,

a length of bar stock. of the desired diameterand has inserted saidstockthrough the spindle and the sleeve i8 and into the collet chucktozthe correct position for the machining. operation. It will be furtherassumed-that :the op rator-has unlocked the finger housing .20 andunscrewed.

the same a number of turns. The operator then causes the parts of thechuck actuating mechanism to move to work-gripping position :asindicatedin Fig. 2. He then screws the finger house log onto thespindleuntilthe jaws of the chuck properly grip the stock,;.and at such timethe rollers. 24 are positioned on the land of the wedge or cone 25 andthe fingers 2| have beenspread the, correct amount. When this. has'beendone, the operator locks the finger housing in adjusted position. Theadjustment referred to having been m-adeit will be understood that whenthe operating lever 42is rocked toward the right, as viewed in thedrawing, the cone will be moved toward the right and into the positionshown inFig. 1, at which time the rollers 24are out of contact with theperiphery of the cone and the jaws of the collet have released theirgrip on the stock. When the operating lever 42 is rocked again towardtheleft, the cone 25 is movedtoward the left until the rollers 24 rideup the conical portion of the cone and engage the cylindrical land, andat such time the fingers have been spread apart and the actuating sleevel8 and collet moved toward the right to cause the collet jaws to gripthe stock. It should be noted that the movements of the parts of theoperating mechanism, as just referred to, occur when a length of stockof the desired diameter is in the chuck. During such movements norelative movement takes place between the part 32 of the two-part link,the link 3! and the lever 28 since the spring 36 holds said parts in therelationship shown in Figs. 1 and 2.

When the collet is gripping a length of stock of the proper diameter theportion 40 of the arm 38 is in abutting relationship with the lug of thepart 33 of the two-part link and at this time the-spring 36 is in itsnormal condition while-the operating handle 42 is in the full lineposition of Figs. 2 and 3.

Assuming that the operator has completed the machining operation on thereferred to length of bar stock of the desired diameter and has insertedanother lengthof stock intothe spindle and chuck and it happens to be ofgreater diameter than the desired one, the following condition willoccur in actuating the chuck. The operator rocks the operating lever 42from chuck open position toward work gripping position, which will rockthe shaft 39 and also cause the power device to function. A resultantmovement of the cone 25 into engagement with the rollers 24 occurs untilthe cone cannot be moved any farther toward the left because the jaws ofthe collet are engaging the larger diameter bar of stock. This resultsinthe rollers 24 engaging the conical wedge periphery of the cone nearto but not: on the circular land for the. reason that -the-sleeve-l8 andthe collet l4 cannot be shifted to their formerright hand work grippingposition. Howeventhe power do vlcef wouldmontinueeto exertaforceron theshaft- 3912c forceitheconeandits actuatinglever .toztheir fullleftsahand;position, zasgindicatedzin Fig. 2.,xwith the result thatexcessive strain would occur in the parts and particularlyzin the:fingers 2|, with .-a consequent likelihood of damaging, bending orbreaking the parts. The arrangement embodying the invention obviatesthis, disadvantage under the -conditions-referredto. Withthe presentarrangement the,continuedi-application of force in the chuck closingdirection to theshaft39 ever-- comes. the strength of'thespringzflfi andcauses thepart-rS-Z of the two-part .link to move-relative-to :theilink3i 'from'the full line position of Fig. :2 into the full line.positionofFig. 3 and to compress the spring "36. During this relativemovement between the linksthe lever 28 is not movedrby theforcebeingsapplied to the-shaft 39. The relative movement between thelinks allows the handle :42=tomove=into the fullline position of Fig. 3butwthei operator will be visually warned that :the chuck is not in fullwork gripping con dition since .as soon as the pressure of his hand isrelieved from the handle 42 the spring 36 will move the links andthe-arm '38 and the handle 42 from the full line position of Fig. 3to-the dot and dash line position thereof, thus partially restoring thehandle to chuck open position. It will be evident that the relativemovement between the links prevents-excessive force beingxapplied to thelever 28, cone '25 and fingers 21, and also results in the handle-42being-returned toward chuck open position. When the invention is appliedto a chuck actuating mechanism which includes a power device foroperatingthe shaft 39 in both the chuck closing and chuck openingdirections and which device is controlled by the position of theoperating handle, it'will be understood that the partial return of theoperating handle toward chuck openposition'initiates the operation ofthe power device to continue this movement of the handle and of theother parts of the actuating mechanism until the chuck is fully opened;in other words, the present invention introduces into the chuckactuating mechanism a safety device which prevents breakage of the parts:and which visually indicates to the operator that the chuck is notfully and properly closed.

In Figs. 5, 6 and 7 there is illustrated a different form of colletchuck and a somewhat different arrangement of the chuck-actuatingmechanism than is shown in Figs. 1 to'3 inclusive. The chuck shown inFig. 6 is a unitary structure attached to the nose of the spindle andcontains no parts mounted'in thespindle bore, thus' enabling the spindleto accommodate diameters of stock up to thediameter ofthe spindle bore,and thistype of chuck is usually employed in the larger bar work ingmachine tools. The work spindle is indicated at 43 while the chuckmounted in the nose of the spindle includes the jaws 44 which areprovided with conical camming surfaces 45. Ashiftable member 46 has aninternal conical camming surface which cooperates withthe cammingsurface 45 to cause the jaws to move inwardly and grip the bar of stock.The member 46 is shifted in the stockgrippingdirection by means offingers 41, which have heel portions 48 contacting an annular shoulderof the shiftable member 46. The fingers '41- float in the chuckand. areprovided with fulcrum points 49" located in an internal roove in anadjusted :ri-ng provided with suitable wrench receiving-openings 50a.-

The chuck furtherincludes a sleeved! which surrounds the chuck bodyandis' slidable axially thereon. The sleeve l is provided with a conicalcamming surface 52' and a cylindrical land surface 53. The sleeve 5! isalso provided externally with an annular groove 54. It will be seen thatwhen the "sleeve 5! is shifted toward the right as viewed in the drawingthe rounded ends of the fingers 41 are permitted to spread outwardlywhen engagingthecamming surface 52 and hence the pressure of the heelportions 48 on the shoulder of the shiftable member 46 is relieved,thusallowing the'jaws of the chuck to release their grip on the stock.Conversely, when the sleeve 5i is shifted toward the left from chuckopen position the rounded ends of the fingers 4T ride up the cammingsurface 52 and onto the cylindrical land surface 53, with the resultthat the fingers are rocked radially inwardly and cause the shiftablemember to move toward the right, thus bringing the jaws radiallyinwardly to grip the stock. The movements of the sleeve 5i just referredto are imparted to the sleeve; by means of shoes 55 carried by theforked upper end of an actuated lever or part 56 and which shoes engagein the annular groove 54 of the sleeve 5 I. V

The lever 56 is fulcrumed intermediate its ends at 51 on a bracket fixedto the bed, while the tudinally split end of the other part 59 of saidtwo-part link and is locked in adjusted position therein by means ofscrews 59a. The opposite end of-the part 59 is pivotally connected to aplate link 66. The plate link 60 in turn is pivotally connected to thefree end of a forked operating arm or part 6!, similar in purpose to theoperating arm or part 38 of the first mentioned form, and which arm 6|is rigidly connected to the operating shaft 62 which is rockablysupported in the bed B of the machine and projects beyond the front wallthereof and has an operatingjever 53 keyed to its projecting endsimilarly as the shaft 39 of the first mentioned form. It will beunderstood that when a power device is used in conjunction with theshaft 62 and the lever 63 said device will be operatively associatedwith said shaft and lever in the manner disclosed in my hereinbeforementioned copending application. The arm 6% has an extended abutment orstop portion 64, the lower end of which engages a fixed stop rod 65 whenthe parts are in the stock gripping position (see Figs. 5 and '7) andacts to limit the movement of the arm 6| and shaft 62 in the chuckclosing direction. The portion 64 is provided with a boss 64a which hasa bore formed therein and in which bore is slidably mounted a springpressed plunger 641), which plunger is engaged by the plate link 60 whenit moves relative to the part 59 of the twopart lipk from the positionshown in Fig. 6 into the full line position of Fig. 7, and said plunger68b exerts a force tending to restore the relationship of the links asindicated in Fig. 6.

The edge of the plate link 66 is provided with a camming portion 66 anda short camming portion 67 substantially at right angles to the portion56, and the purpose of which camming portions will later be pointed out.

,The part 59 of the two-part link is provided with an angularlypositioned bore 68, in which is slidably mounted a hollow plunger 69that has a; forked outer end straddling the plate link 66 and mounting aroller 10, which is in contact:

with either the camming portion 66 or the camming portion 61 of theplate link, depending upon the conditions of operation of the mechanism.A coil spring H is mounted in the bore 68, and one end of said springextends into the hollow plungor B9 and maintains the plunger normally inhottomed engagement with a shoulder in the bore, while the other end ofthe spring extends into and abuts a cup-shaped screw cap 12 mounted inthe bore. a

So long as the bar of stock in the chuck is of the desired diameter theparts will be in the re lationship shown in Figs. 5 and 6, respectively,

when in chuck open or chuck closed position, and at such times norelative movement will occur between the part 59 and the plate link 60.How' ever, should a bar of stock of larger diameter than the desireddiameter be placed in the chuck and the parts of the actuating mechanismmove:

toward chuck closed position such larger bar of stock will prevent theparts from attaining their full chuck closed position, but should theapplication of force against said part continue the link 60 will swingrelative to the part 59 from the full line position of Fig. 6 into thefull line position of Fig. 7, with the camming surfaces of the platelink'acting on the roller 10 and compressing the spring H. This relativemovement of the plate link allows the arm 6|, shaft 62 and lever 63 tomove into full work gripping position, but such movement does not impartany further movement or additional force to the part 59 and the actuatedlever 56 in the chuck closing direction. When the parts are in theposition shown in Fig.

- 7-the plate link 60 has engaged the plunger 64b and moved the sameinwardly to compress its sprin As soon as the operator releases his holdon the handle 63 the spring pressed plunger 64b, in conjunction with thespring pressed plunger 69, will exert a force on the plate link 60 torock the same from its full line position of Fig. '7 back to its fullline position of Fig. 6, with a resultant movement of the arm 6|, shaft62 and handle 63 toward chuck open position, thus indicating to theoperator that the chuck has not been properly closed so as to correctlygrip the bar of stock.

Figs. 9 to 12 inclusive illustrate another form of actuating mechanismwhich can be used in conjunction with the collet chuck illustrated inFig. 6. This modified form of actuating mechanism likewise includes theactuated lever 56 and a link 13 corresponding in general with thetwo-part link 58, 59 shown in Figs. 5 and 6. The link 13 includes a part14 at one end thereof corresponding with the part 58 of Fig. 6 and whichis pivotally connected with the lever 56. The opposite end of the lever13 is pivotally connected with a member 15 which is freely rockable on ashaft-16 which corresponds with the shaft 62 of Fig. 6. Amember Tlforming a part of the operatingmeans is keyed to the shaft 16 and isadapted to be rocked by means of an operating lever (6a which is alsokeyed to the shaft and corresponds with the lever 63 of Fig. 6. Themember 11 is here shown as having forked portions 18, the lower ends ofwhich are adapted for abutting cooperation with a fixed stop rod 19corresponding with the stop rod 65 of Fig. 6.

The-freely rockable member 15 is connected with the member H by means ofa pair of links and 8|, the latter of which carries a lug 82 having acam surface 83 thereon.1 The adjacent; ends oi; the e Link a ni allr nncted rthe Din wand-their, outern s are; r vq a connected with themembers 15 and 11- by the pinsfllia and 81a, The elements 89 and; 8 lthus, form a yieldable connection or articulated linkage; A retaining;pawl 84 is pivotally mounted; in. the forked portion 78 of the member1;! and cooperates with the lug 82 through a roller .85 which engagesthe cam portion 83; A plun er 85; is. movably mounted in the member 11and is urged: by a spring 81 against the retaining pawl; 84.: forcausing the latter to retain the links 8i and 8|; inthe relativeposition shown in Figs, 9 and 10 for the transmission ofpush lf g andpullme forces between-the members (5, and 1.7 during the. normaloperation of the mechanism. This action of the retaining. pawl 8.4 issupplemented by or followed. by the action ofa pair of tension springs88 which have their ends connected re,-. spectively with the pivot pin89. of' the links 80. and BI and an anchor pin 99. carried by themember-l1.

In the modified actuating mechanism just de-. scribed above, it will beobserved that Fig. 9; shows the mechanism in the chuck released p01.sition. VWhen actuating force is applied to the shaft 16- through thelever 76a in a chuck closing direction either manually or by a suitablepower device, the member 11 is swung to a chuck closed position in whichthis member is in engagement with the fixed stop rod as shown in Fig.10. Ifthe diameter of stock is such as to permit proper closing of thechuck no relative movement occurs between the members l1 and and, asshown in Fig. 10., the links 89 and 8t remain in their normal operatingposition and the corre sponding normal relative position for the link 13is such that the parts are locked in a position corresponding with thechuck closed condition by means of a toggle action similar to thatobtained in the actuating mechanisms previously described herein.

If oversize stock has been placed in the chuck and an attempt is made toclose the chuck, the member 11 will be moved to its fully actuated:position in engagement with the fixed stop rod 19, as shown in Fig. 12,if sufficient force has been applied but the actuated lever 5t will notbe moved; to a chuck closed position because of thQ'OVGISiZE characterof the stock. The link 13 will likewise be prevented from moving to itsnormal chuck closed position and this abnormal condition will result ina relative rocking or closing movement between the members 11- and 15and about theaxis of the shaft Hi, and this relative movement causes thelinks 80 and 8| to be collapsed to the position shown in Fig. 12. lhismovement of the links 8i} and BI to their collapsed-position takes placeinitially against the holding'ipr-ce of the retaining pawl 84 andsubsequently against the tension ofthe springs- 88. When the mechanismhas been actuated, by the appll-cation'of 'sufficient force, to producethe collapsed condition; shown in Fig. 12 and the operatorremoves hishand from the operating lever or the power control member thereon, thepull or the springs 88 will restore the links 38 and BI to' their normalposition shown in Fig. 9 and, in so doing, produces a rotative movementof the member 11 in a clockwise direction therebyrocking the shaft 16and the operating lever;- Tea connected therewith and thisreturnmovement oftheoperating lever informs the operator that the chuckhas not been closed.

Although several embodiments of the invent0 tion have. been. illustratedand described. herein, it shouldbeunderstood that the. invention. is,sus: ceptibleof various. modifications and adaptations within the scopeof. the. appended claims.

Having thus described nay-invention, I claim:

1. Inthe. actuatingmechanism of a work gripe pin-g device. having anoperating. part and an actuated parti an operative connection betweensaid parts and including a pair of relatively moyableelementsfoperatively connected respectively. with said parts, meansinterconnecting said elements and spring meansv operatively sociatedwithsaidelements and resisting, with a predetermined force, relativemovement therebetween during the actuation of the device in, the workgripping direction and adapted to be stressed when saidv force isexceeded, whereupon relative movement occurs between said elements.

and said spring acts through said elements to;- move said operating;part in the work releasing dire ti n 2 In the actuating mechanism of awork gripe ping device havin an. Operating pa t nc udin hand e an an; aca ar p m e n negation between said: parts andincluding relativelymovable elements operatively connected respectively with said par-ts,means interccnnecte ing said: elements and spring means opfli tivelyassociated with said; elements. and maintaining the same, with apredetermined force against relative movement and in normal; operativerelationship, said spring means, elements and partsbeingso disposedthatwhen said force isexceeded duringthe operation of; the mechanism in:the

workgrippingdirection, relative movement occurs between said; elements,and said springmeans is stressed and tends tov res-tore sa d elements totheir normal; operative relationship and tomove the operating part andthe handle in the work releasing direction; 5

3-, In the actuating mechanism of a work grip-- ping device having anoperatingpart and an; ao-

tuatedpart;- an operative connection betweensaidparts and including apair of pivotallyinterconnectedelements pivotallyconnectedrespectivelywith said parts, and spring means-opera tively associated;with'said; elements and maintaining the same; with a predetermined forceagainst. relativemo m nt.- e e etwe n and-innormal operatingrelationship, said; spring means, e ents and parts bei g so d pose th twhen said predetermined force is exceeded during the actuation oithemechanism in the work gripping direction, relative movement occursbetween: said elements, and said spring means is, stressed andacts torestore said elements to their normal onerative relationship and to movesaid: operating part in. the work releasing'dire'ction.

4. In the actuating-- mechanism of a wo'rk'gr-ipping devicehavinganoperating part and an actuated part; fan operative connectionbetween aid. Pa s swimmin #1 r fr i' v n rconnected elements operativelyconnected respectively w th sa d arts. and p in mean aran ed. o! e r aprede erm ne lo ceasains the. element which is. Connected to theOperating part and to maintain said elements in normal darted to bestressed hen sa orce s c ded urin actua ion f; the echani m nherk.

gripping dire tion, wher upon relative nicv n en occurs between said:elements, and-said. spring meansacts. to-restoresaid: elements to theirnor-.

11 mal operative relationship and to move said operating part in thework releasing direction.

In the actuating mechanism of a work gripping device having an operatingpart and an actuated part; an operative connection between said partsand including a pair of pivotally interconnected links, with said linkspivotally connected respectively to said parts, and spring meansresisting with a predetermined force, relative pivotal movement betweensaid links and maintaining the same in normal operative relationship,said spring means being adapted to be stressed when said force isexceeded during the actuation oi the device in the work grippingdirection, whereupon relative pivotal movement occurs between saidlinks, and-said spring means acts to restore said links to normaloperative relationship and to move said operating part in the workreleasing direction.

6. In the actuating mechanism of a work gripping device having anoperating'lever including a handle and an actuated lever; an operativeconnection between said levers and including a .pair of pivotallyinterconnected links which are pivotally connected respectively to saidlevers, and spring means operatively associated with said links andresisting, with a predetermined force, relative pivotal movementtherebetween gand maintaining said links in normal operative"relationship, said links :and said spring means being arranged thatwhen said force is exceeded during the actuation of the mechanism in the,work gripping direction, relative pivotal movement occurs between saidlinks and said spring means is compressed and acts upon said links to.restore the same to normal operative relationship between said linksand to maintain said links in normal operative relationship, said linksand spring means being so arranged that when said 7 force is exceededduring theactuation of the mechanism in the work gripping direction,relative pivotal movement occurs between said links and saidspring'means is compressed and acts to restore said links to normaloperative relationship and to move said operating lever and handle inthe work releasing direction.

8. In the actuating mechanism of a work gripping device having anoperating lever including a handle and an actuated lever; an operativeconnection between said levers and including a pair of pivotallyinterconnected links which are pivotally connected respectively to saidlevers, and spring means carried by said actuated lever and acting, witha predetermined force, against .thelink which, is connectedto saidoperating lever to resist relative movement between said links and tomaintain the same in normal operative relations-hip, said links, leversand spring means being so disposed that when said force is exceededduring actuation of said mechanism in the work gripping direction,relative movement occurs betweensa'id links and said spring iscompressed and acts to restore said links to normal operativerelationship and to move said operating 12 lever and handle in the workreleasing direction.

9. In the actuating mechanism of a work gripping device having anoperating lever including a handle and an actuated leveryan operativeconnection between said levers and including a pair of pivotallyinterconnected links which are pivotally connected respectively to saidlevers, and spring means carried by one of said links and acting againstthe other thereof to resist, with a predetermined force, relativepivotal movement therebetween and to maintain the same in normaloperative relationship, said links, parts and spring means being sodisposed that when said force-is exceeded during the operation of themechanism in the work gripping direction relative pivotal movementoccurs between said links, and said spring means is compressed and actsto restore said links to normal operative relationship and to move saidoperating lever and handle in work releasing direction.

10. In the actuating mechanism of a work gripping device having anoperating lever ineluding a handle and an actuated lever; an operativeconnection between said levers and including a pair of pivotallyinterconnected links which are pivotally connected respectively to saidlevers, and spring means carried by said link which is pivotallyconnected to said actuated lever and acting on said link which ispivotally connected to said operating lever to resist, with apredetermined force, relative pivotal movement between said links and tomaintain the same in normal operative relationship, said levers, linksand spring means being so disposed that when said force is exceededduring the actuation of the mechanism in the work gripping direction,relative pivotal movement between said links occurs and said springmeans is compressed and acts to restore said links to normal operativerelationship and to move said operating lever and handle in the workreleasing direction.

11. In the actuating mechanism of a work gripping device as defined inclaim 10, supplemental spring means operatively associated with saidlinks and acting, when relative movement occurs between said links, inconjunction with said first mentioned spring means to restore said linksto normal operative relationship.

12. In a collet chuck actuating mechanism of the type having a rockableoperating lever including a handle, an actuated lever and a shiftablecollet actuating cone operatively connected with said actuated lever; anoperative -connec-,

tion between said levers and including a pair of 'pivotallyinterconnected links which are pivotally connected respectively withsaid operating lever and said actuated lever, and spring meansoperatively associated with said links and. exerting predetermined forcethereon to resist relative movement therebetween and maintain the samein normal operative relationship, said spring means being compressedwhen said cone is prevented from having its normal operative movementduring chuck closing actuation of the mechanism, at which time saidlinks move relative to each other and provide for complete operativemovement of said operating lever and handle while said spring acts torestore said links to normal operative relationship and to rock saidoperating lever and handle in the chuck releasing direction. I

13. In a collet chuck actuating mechanism of the type having anoperating lever including a handle, a rockable actuated lever,a slidablecone actuated by said actuated lever and p ovided 13 with aconicalcamming surface and a cylindrical land, and rockable chuckclosing fingers provided with rollers enga geable by said cone andnormally contacting said land when the chuck is in stock grippingengagement; an operative connection between said levers. and includin apair of pivotally interconnected links which are pivotally connectedrespectively with said operating lever and said actuated lever, andspring means operatively associated with said links and resistingrelative "movement therebetween when said levers, cone and fingers'canmove tonormal work gripping position during the actuation of themechanism but which, when the rollers do'not reach a position on theland of the cone during chuck closing actuation, said spring iscompressible upon continued movement of the operating lever to allowrelative movement between said links and then to restore said links tonormal operating relationship and move said operating lever in the chuckopening direction.

14. In the actuating mechanism of a work gripping device, an operatinglever, an actuated lever,'and an operative connection between saidlevers, and including a link having one of its ends pivotally connectedto said operating lever, said actuated lever being provided with anopening therethrough and extending longitudinally thereof, a second linkpivotally connected at one of its ends to said actuated lever withinsaid opening and having its other end pivotally connected to the otherend of said-first named link, said actuated lever being provided with alongitudinal bore communicating with said opening, a plunger slidable insaid bore and having an operative association with said first. nazmedlink, and a spring mounted in said bore and acting on said plunger toexert its force through said plunger against said link to resistrelative movement between said links.

15. In the actuating mechanism of a work gripping device, an operatinglever, an actuated lever, and an operative connection between saidlevers and including a link having one of its ends pivotally connectedto said operating lever, a second link having one of its ends pivotallyconnected to said actuated lever and its other end pivotally connectedto the other end of said first named link, spring pressed means carriedby said actuated lever and acting against said first named link, saidactuated lever and said second link having cooperating means limitingmovement of said links in a direction to compress said spring pressedmeans.

16. In the actuating mechanism of a work gripping device, an operatinglever, an actuated lever and an operative connection between said leversand including a relatively short link pivotally connected to saidoperating lever, a relatively long link pivotally connected at one endto said actuated lever and at the other end to said relatively shortlink, said relatively long link being provided with an elongated bore, aplunger mounted in said bore and operatively engaging said relativelyshort link, and a spring mounted in said bore and acting on said plungerto resist relative movement between said links.

17. An actuating mechanism of a work gripping device as defined in claim16, and wherein said relatively short link is provided on its edge witha pair of adjacent camming surfaces and with which said plunger isoperatively associated during difierent operating conditions of saidmechanism.

18. An actuating mechanism of a work grip- 14 ping device as definedinclaim 14, and wherein supplemental spring means is provided which actson said short link when said plunger is depressed againstits spring,said plunger and said supplemental spring means acting to move saidlinks to their normal operative relationship.

19. In the actuating mechanism of a work gripping device, a rockableoperating member, a rockable actuated member, and an operatingconnection between said members comprising a pair of pivotallyinterconnected elements pivotally connected respectively with saidmembers and spring means including a tension spring, associated withsaid elements and maintaining the same against relative movementtherebetween and in normal operating relationship, said spring means,elements and members being so disposed that when a predetermined forceis exceeded during the actuation of the mechanism in the work grippingdirection relative movement occurs between said elements, and'saidspring means acts to restore said elements to their normal operatingrelationship and to move said operating member inv the work releasingdirection.

20. In the actuating mechanism of a work gripping device, a shaft, anoperating member and an actuated member associated with said shaft andadapted for relative rocking movement about the axis thereof,articulated linkage connecting said members and having anormal positionfor holding said members against relative rocking movement during theapplication of a predetermined force to said work gripping device, saidlinkage being yieldable to permit relative rocking movement between saidmembers in rc-- sponse to the application of an abnormal force to saidwork gripping device, and means resisting the yielding of said linkage.

21. In the actuating mechanism of a work gripping device, a shaft, anoperating member and an actuated member associated with said shaft andadapted for relative rocking movement about the axis thereof,articulated linkage connecting said members and having a normal positionfor holding said members against relative rocking movement during theapplication of a predetermined force to said work gripping device, saidlinkage being yieldable to permit relative rocking movement between saidmembers in response to the application of an abnormal force to said workgripping device, means carried by one of said members and cooperatingwith the linkage for yieldably retaining the same in said normalposition, and spring means for restoring the linkage to said normalposition.

22. In actuating mechanism for a chuck, a chuck actuating lever, anoperating lever movable in chuck closing and chuck opening directionsand mechanism operatively connecting the chuck actuating lever with saidoperating lever comprising a pair of relatively rockable membersconnected respectively with said chuck actuating lever and saidoperating lever, articulac'ted linkage connecting said members andhaving a normal position for holding said members against relativerocking movement during the application of a predetermined force to saidchuck actuating lever in response to movement of said operating lever ina chuck closing direction, said linkage being yieldable to permitrelative rocking movement between said members upon the application ofan abnormal operating force to said chuck actuating lever, and springmeans resisting the yielding of the linkage and also acting to restorethe linkage to its normal position and cause movement of said .operatinglever in a chuck opening direction.

23. In actuating mechanism for a chuck having an actuating lever, ashaft, an operating lever connected with said shaft for rocking thesame, a member connected with said shaft and adapted to be rockedthereby, a second member rockable on the first mentioned member, meansconnecting the second member with said chuck actuating lever,articulated linkage connecting said second member with the firstmentioned member and having a normal position for holding said membersagainst relative rocking movement during the application of apredetermined operating force to said chuck actuating lever, saidlinkage being yieldable in response to the application of an abnormaloperative force to said chuck actuating lever so as to permit relativerocking between said members, and spring means resisting the yielding ofsaid linkage and acting to restore the linkage to said normal position.

24. In the actuating mechanism of a work gripping device having anoperating part and an actuated part; a safety connection between saidparts for transmitting movement of said operating part to said actuatedpart and comprising a pair of elements operatively connectedrespectively with said parts, means interconnecting said elements forrelative movement therebetween, and force applying means operativelyassociated with said elements and acting with a predetermined force tonormally maintain said elements in a predetermined relationship whereinsaid elements impart movement of said operating part to said actuatedpart, said force applying means being overcome when said predeterminedforce is exceeded during the actuation of the device in the workgripping direction and prior to said device attaining its final workgripping position to allow relative movement between said elements outof their normal rela- Number tionship to thus terminate the movement inthe work gripping direction of said actuated part by said operatingpart, said force applying means then acting to restore said elements totheir normal relationship and to move said operating part in the workreleasing direction.

25. In the actuating mechanism of a work gripping device having anoperating part and an actuated part; a safety connection between said.parts for transmitting movement of said operating part to said actuatedpart and comprising a pair of elements operatively connectedrespectively with said parts, means interconnecting said elements forrelative movement therebetween, and spring means operatively associatedwith said elements and acting with a predetermined force to normallymaintain said elements in a predetermined relationship wherein saidelements impart movement of said operating part to said actuated part,said spring means being overcome when said predetermined force isexceeded during the actuation of the device in the work grippingdirections and prior to said device attaining its final work grippingposition to allow relative movement between said elements out of theirnormal relationship to thus terminate the movement in the work grippingdirection of said actuated part by said operating part, said springmeansthen acting to restore said elements to their normal relationship and tomove said operating part in the work releasing direction.

FRED H. BOGART.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Name Date 1,261,757 Brophy Apr. 9, 1918

